In networking environments that include devices or nodes on a network coupled to the Internet, the nodes may move and/or become mobile (e.g., mobile network nodes “MNNs”). In this environment, maintaining a continuous network connection with these MNNs due to that movement is difficult. For example, an MNN utilizes Mobile Internet Protocol Version 6 (MIPv6) to communicate with another node on a network that couples to the Internet. In this example, the MNN moves such that its point of attachment to the Internet has changed and is different than its previous point of attachment. A point of attachment, for example, may be a link to an access point (wired or wireless) for a network that couples to the Internet. The network that couples to the Internet may include, but is not limited to, wired or wireless local area networks (LAN/WLAN), wide area networks (WAN/WWAN), metropolitan area networks (MAN), personal area networks (PAN) and cellular or wireless broadband telephony networks.
Typically, a network address (e.g., IPv4 or IPv6 address) is associated with the MNN's point of attachment to the Internet. When the MNN's point of attachment changes, another network address is associated with the MNN's new point of attachment to the Internet. This may result in a corresponding change in the MNN's network address. Simply changing the MNN's network address based on a change in the point of attachment may allow the MNN to communicate with another node uninterrupted, for example, at the Open Systems Interconnection (OSI) data link layer. However, the MNN may be a mobile handheld or notebook personal computer that has established higher layer connections (e.g., transport and higher levels) with another node. These higher layer connections (e.g., a virtual private network (VPN) connection) may be based on the MNN maintaining a specific network address. Due to authentication requirements, these higher layer connections between the MNN and the node likely cannot be maintained by just changing the network address.
Industry initiatives have tried to address a possible interruption in communications via higher level connections. These initiatives allow an MNN to move from one point of attachment to another without changing the address to which other nodes may forward data to the MNN. Thus, the MNN's network address from the perspective of other nodes has not changed. One such initiative is the Internet Engineering Task Force, Network Working Group, Request for Comments: 3775, Mobility Support in IPv6, published June 2004 (“RFC 3775”). RFC 3775 describes a MIPv6-based communication protocol that allows an MNN to move from one point of attachment to another without changing the network address some or most other nodes may use to communicate with that MNN. This is accomplished by giving the MNN a home address that is associated with its original or initial point of attachment to the Internet. This original or initial point of attachment is typically referred to as the home link. Other nodes will forward communications to a node (e.g., a router) on the home link using that home address associated with the home link. Communications are then forwarded to the MNN by the node on the home link. Thus, as the MNN moves to different points of attachment, that movement is transparent to higher layer connections with other nodes.
Another industry initiative addresses instances where an MNN is part of a network that also moves and/or becomes mobile (“mobile network”). One such initiative is the Internet Engineering Task Force, Network Working Group, Request for Comments: 3963, Network Mobility (NEMO) Basic Support Protocol, published January 2005 (“RFC 3963”). RFC 3963 describes a protocol that allows every node coupled to a mobile network to maintain communications with other nodes in or outside of the mobile network while the mobile network moves around and changes its point of attachment to the Internet. The mobile network may couple to the Internet through a node that is also mobile or becomes mobile and has routing capabilities, e.g., a mobile router. In that sense, the mobile network is commonly called a nested network when coupled to another router that is part of another network.